Innovative tools for rapidly mapping / quantifying CO2 leakage and determining its origin

Although deployment of onshore CO2 storage will be crucial to reach the EU’s ambitious goal of an 80% reduction in greenhouse gas emissions by 2050, some stakeholders are concerned about potential risks if CCS is situated on land near populated areas. The EU-funded, Horizon 2020 project ENOS (ENabling Onshore CO2 Storage in Europe) is addressing many of these concerns about onshore storage by demonstrating best practices through pilot-scale projects and field laboratories, integrating CO2 storage in local economic activities, and creating a favorable environment through public engagement, knowledge sharing and capacity building/training. As part of this work, ENOS is using sites where natural, geologically produced CO2 is leaking to the surface, to test innovative monitoring tools and to better understand gas migration pathways and early warning signs that could be detected in the unlikely event of CO2 leakage. At least four natural leakage sites are being used in central Italy, including the well-known Latera caldera as well as San Vittorino valley, Ailano, and Fiumicino. All sites exhibit the leakage of almost pure CO2 along bedrock faults and through overlying sediments prior to release to the atmosphere, but each has unique characteristics related to the origin of the leaking gas, the composition of the local bedrock, depth to water table, soil properties, and ground surface conditions. Results from recent ENOS field campaigns at these sites are presented, focusing on data and interpretation related to i) large area, rapid leakage mapping and quantification tools; ii) innovative methods to determine the source of a CO2 anomaly; iii) CO2 leakage style as a function of near-surface conditions.